Merlo Transmission Surging

[Farmer Piles]

Just an FYI for other Merlo owners out there.
Our 32.6, 11 years old, has been a great servant but over the last couple of years it has been prone to transmission surging and running at half speed or less when the engine is at full revs. Talked to the local dealer who had no ideas or advice. Nothing came back from Merlo either. I had changed the transmission oil filter and regularly, and frequently emptied the header tank and put fresh high spec hydraulic oil in. This always cured the problem for a few weeks, plus a good way to refresh the transmission oil without draining the system - which I have been told is a big no, no.
Anyhow, long story short, the pressure switch on the back of the solenoid block was leaking. 20 minute job to replace it and about £130, but problem solved.
And no thanks to Merlo or their agents.

 

[Farma Parma]

Just an FYI for other Merlo owners out there.
Our 32.6, 11 years old, has been a great servant but over the last couple of years it has been prone to transmission surging and running at half speed or less when the engine is at full revs. Talked to the local dealer who had no ideas or advice. Nothing came back from Merlo either. I had changed the transmission oil filter and regularly, and frequently emptied the header tank and put fresh high spec hydraulic oil in. This always cured the problem for a few weeks, plus a good way to refresh the transmission oil without draining the system - which I have been told is a big no, no.
Anyhow, long story short, the pressure switch on the back of the solenoid block was leaking. 20 minute job to replace it and about £130, but problem solved.
And no thanks to Merlo or their agents.

Aye thats poor service mind...
My 28.7 at 4600 odd hours now sort of hunts the revs when there lower than say 1500 around moving slowly to do things
so far dealer is puzzled why? not that they have really looked at it but i'll be pushing them at some point.
Another farmer i know has a similar machine but with 8000hrs on & his does similar thing
he says its the main hydraulic pump worn on his as it wont lift what it used too
Mine lifts it full cap no bother.
I did replace the electric diesel filter & pump as it died a couple of months back & i thought it was better afterwards for a while
but its still doing this ever so slightly again now.
Give it more revs & no issues whatsoever tho.
Still a fab telehandler tho & no idea how i can ever rep it like for like seeing there more than double the price this was in 2005

 

[Farma Parma]

It starts n stops instantly & plenty power no diff to day1

 

[Farmer Piles]

Ours has only done 4500hrs. Generally a great handler.

 

[Farmer Piles]

Well, a change to all that. It started losing speed and oomph again today. Engine fine. Strangely though, if I put my foot on the brake whilst moving then the transmission puts power to the wheels again. Almost as though it needs the resistance to make it drive.
I can only think that there must be pressure sensors that regulate load and power to the wheels.
Any suggestions welcome.
And no, I am not reckoning to change it.

 

[Planttech]

Aye thats poor service mind...
My 28.7 at 4600 odd hours now sort of hunts the revs when there lower than say 1500 around moving slowly to do things
so far dealer is puzzled why? not that they have really looked at it but i'll be pushing them at some point.
Another farmer i know has a similar machine but with 8000hrs on & his does similar thing
he says its the main hydraulic pump worn on his as it wont lift what it used too
Mine lifts it full cap no bother.
I did replace the electric diesel filter & pump as it died a couple of months back & i thought it was better afterwards for a while
but its still doing this ever so slightly again now.
Give it more revs & no issues whatsoever tho.
Still a fab telehandler tho & no idea how i can ever rep it like for like seeing there more than double the price this was in 2005

Have you gone through the fuel system? Including draining and flushing the tank? I assume it is a 28.7kt so maybe worth checking for slack in the idler timing gear.

 

[Planttech]

Just an FYI for other Merlo owners out there.
Our 32.6, 11 years old, has been a great servant but over the last couple of years it has been prone to transmission surging and running at half speed or less when the engine is at full revs. Talked to the local dealer who had no ideas or advice. Nothing came back from Merlo either. I had changed the transmission oil filter and regularly, and frequently emptied the header tank and put fresh high spec hydraulic oil in. This always cured the problem for a few weeks, plus a good way to refresh the transmission oil without draining the system - which I have been told is a big no, no.
Anyhow, long story short, the pressure switch on the back of the solenoid block was leaking. 20 minute job to replace it and about £130, but problem solved.
And no thanks to Merlo or their agents.

Which pressure switch did you change?

 

[Planttech]

Well, a change to all that. It started losing speed and oomph again today. Engine fine. Strangely though, if I put my foot on the brake whilst moving then the transmission puts power to the wheels again. Almost as though it needs the resistance to make it drive.
I can only think that there must be pressure sensors that regulate load and power to the wheels.
Any suggestions welcome.
And no, I am not reckoning to change it.

This fault has me intrigued. I have sent you a message

 

[Sledgehammer]

Does the 32.6 have a variable displacement motor? it could be related to the control block on it. You'd likely need to stick a guage on a few of the test ports to know whats happening.

 

[Farma Parma]

Have you gone through the fuel system? Including draining and flushing the tank? I assume it is a 28.7kt so maybe worth checking for slack in the idler timing gear.

No not touched other than a filter change every 18months or so.
Did the filter & its pump this time & its had a pump before but oh crikey 7-8years back.
Its got full power instantly if you floor it. & starts on the button
no issues otherwise, My Filtered Diesel only ever put in its tank.
When i changed that pump n filter nowt else in the diesel no bio sludge at all

 

[Farma Parma]

Have you gone through the fuel system? Including draining and flushing the tank? I assume it is a 28.7kt so maybe worth checking for slack in the idler timing gear.

Soz yeah 28.7KT

 

[Farmer Piles]

Have you gone through the fuel system? Including draining and flushing the tank? I assume it is a 28.7kt so maybe worth checking for slack in the idler timing gear.

It's not the engine, just the transmission.

 

[Farmer Piles]

Which pressure switch did you change?

It was the one on the solenoid block that has the brakes, near the front under the cover between the engine and the cab. It was leaking oil, especially when I drove forward.

 

[Courier]

Aye thats poor service mind...
My 28.7 at 4600 odd hours now sort of hunts the revs when there lower than say 1500 around moving slowly to do things
so far dealer is puzzled why? not that they have really looked at it but i'll be pushing them at some point.
Another farmer i know has a similar machine but with 8000hrs on & his does similar thing
he says its the main hydraulic pump worn on his as it wont lift what it used too
Mine lifts it full cap no bother.
I did replace the electric diesel filter & pump as it died a couple of months back & i thought it was better afterwards for a while
but its still doing this ever so slightly again now.
Give it more revs & no issues whatsoever tho.
Still a fab telehandler tho & no idea how i can ever rep it like for like seeing there more than double the price this was in 2005

I might be wrong but I would imagine that the Transmission Pump is a 10,000 ? PSI pump and the Lifting pump is a separate 3,000 ? psi system probably fed from the same reservoir - Certainly that was the layout on FDI-Sambron hydrostatic machines .

There's not much these guys ( https://greenhandlers.co.uk/about-us ) have not come across before with Merlos, they have 600+ out on hire and service anywhere in the UK and maybe beyond .

 

[Farmer Piles]

The transmission has its own filter and reservoir, separate from the hydraulics. Thanks for the link.

 

[Planttech]

I might be wrong but I would imagine that the Transmission Pump is a 10,000 ? PSI pump and the Lifting pump is a separate 3,000 ? psi system probably fed from the same reservoir - Certainly that was the layout on FDI-Sambron hydrostatic machines .

There's not much these guys ( https://greenhandlers.co.uk/about-us ) have not come across before with Merlos, they have 600+ out on hire and service anywhere in the UK and maybe beyond .

Two separate systems

 

[Planttech]

No not touched other than a filter change every 18months or so.
Did the filter & its pump this time & its had a pump before but oh crikey 7-8years back.
Its got full power instantly if you floor it. & starts on the button
no issues otherwise, My Filtered Diesel only ever put in its tank.
When i changed that pump n filter nowt else in the diesel no bio sludge at all

What fuel pump did you fit? Vapormatic ect or Perkins?

 

[Courier]

Two separate systems

So this guy above must have two separate problems

"Another farmer I know has a similar machine but with 8000hrs on & his does similar thing
he says its the main hydraulic pump worn on his as it wont lift what it used too..."

 

[Planttech]

So this guy above must have two separate problems

"Another farmer I know has a similar machine but with 8000hrs on & his does similar thing
he says its the main hydraulic pump worn on his as it wont lift what it used too..."

Yes agree worn pump won’t cause engine to hunt.

 

[Farma Parma]

What fuel pump did you fit? Vapormatic ect or Perkins?

Genuine Perkins like for like part via Agco Dealer in Agco outer box
There not cheap, i see Kramp does them for 1/3 of the money? pic says its a perkins
Might get one too keep as a spare & it it was the same there is big rip off going on at main dealer.. (Doesn't surprise me)